The staffs of the SEC CFTC released its long-awaited joint report presenting their findings regarding the market events of May 6, 2010. The report will be presented to the Joint CFTC-SEC Advisory Committee on Emerging Regulatory Issues. Here are excerpts on principal lessons:

One key lesson is that under stressed market conditions, the automated execution of a large sell order can trigger extreme price movements, especially if the automated execution algorithm does not take prices into account. Moreover, the interaction between automated execution programs and algorithmic trading strategies can quickly erode liquidity and result in disorderly markets. As the events of May 6 demonstrate, especially in times of significant volatility, high trading volume is not necessarily a reliable indicator of market liquidity.

May 6 was also an important reminder of the inter-connectedness of our derivatives and securities markets, particularly with respect to index products. .... [T]he staffs of the CFTC and SEC are working together with the markets to consider recalibrating the existing market-wide circuit breakers – none of which were triggered on May 6 – that apply across all equity trading venues and the futures markets.

Another key lesson from May 6 is that many market participants employ their own versions of a trading pause – either generally or in particular products – based on different combinations of market signals. While the withdrawal of a single participant may not significantly impact the entire market, a liquidity crisis can develop if many market participants withdraw at the same time. This, in turn, can lead to the breakdown of a fair and orderly price-discovery process, and in the extreme case trades can be executed at stub-quotes used by market makers to fulfill their continuous two-sided quoting obligations. ...

A further observation from May 6 is that market participants’ uncertainty about when trades will be broken can affect their trading strategies and willingness to provide liquidity. ...

Going forward, SEC staff will evaluate the operation of the circuit breaker program and the new procedures for breaking erroneous trades during the pilot period. As part of its review, SEC staff intends to assess whether the current circuit breaker approach could be improved by adopting or incorporating other mechanisms, such as a limit up/limit down procedure that would directly prevent trades outside of specified parameters, while allowing trading to continue within those parameters. ...

Of final note, the events of May 6 clearly demonstrate the importance of data in today’s world of fully-automated trading strategies and systems. This is further complicated by the many sources of data that must be aggregated in order to form a complete picture of the markets upon which decisions to trade can be based. ...

Whether trading decisions are based on human judgment or a computer algorithm, and whether trades occur once a minute or thousands of times each second, fair and orderly markets require that the standard for robust, accessible, and timely market data be set quite high. Although we do not believe significant market data delays were the primary factor in causing the events of May 6, our analyses of that day reveal the extent to which the actions of market participants can be influenced by uncertainty about, or delays in, market data.

Accordingly, another area of focus going forward should be on the integrity and reliability of market centers’ data processes, especially those that involve the publication of trades and quotes to the consolidated market data feeds. In addition, we will be working with the market centers in exploring their members’ trading practices to identify any unintentional or potentially abusive or manipulative conduct that may cause system delays that inhibit the ability of market participants to engage in a fair and orderly process of price discovery.